Health Care Professional Information

Transfer factors are a complex group of more than 200 highly polar, hydrophilic, low molecular weight (less than 12,000 Daltons) proteins produced in small quantities by lymphoid cells (1). Their precise molecular structure has not been determined. They carry with them the parent lymphocyte's delayed-type hypersensitivity and cell-mediated immunity and pass it along to non-immune recipients, and appear to function across species. Transfer factors can be extracted from human or animal white blood cells, cloned lymphocytes grown in vitro, colostrum, and egg yolk. They appear to be well tolerated and in clinical settings have shown some signs of efficacy in treatment of herpes (2), acute infection in children (3), chronic fatigue syndrome (4), and Candidiasis (5). One study showed effectiveness in increasing white blood cells, CD8 lymphocytes and interleukin 2 levels among patients with HIV (6). Transfer factors are ineffective in treating hepatitis (7), multiple sclerosis (8), extrinsic bronchial asthma (9), human warts (10), juvenile rheumatoid arthritis (28), and acne vulgaris (11).
Studies have shown transfer factors ineffective in treating malignant melanoma (12), nasopharyngeal carcinoma (13), bronchogenic carcinoma (14), Hodgkin's disease (15), osteogenic sarcoma (16), and mycosis fungoides (17). In rats, transfer factors were shown to reduce tumor size and increase peripheral blood T-lymphocyte counts (21). Transfer factors show signs of effectiveness in increasing survival rates among patients with Stage I adenocarcinoma of the lung (18) and Stage I cervical cancer (19), but further research is warranted. In a study of children with leukemia, immunization with transfer factors conferred protection against varicella-zoster infection (20).
Overall, there is a paucity of large randomized controlled clinical trials, and a need for further research into the effectiveness of transfer factors.

Though the exact mechanisms of transfer factors remain unknown, they contain many molecules, some of which act in an antigen-specific manner, while others have been shown to have immunomodulating capabilities (1). Human leukocyte dialysates (DLE) contain low molecular peptides that were characterized in the late 1980s as amino terminal ends of enkephalins. A low molecular weight sub fraction derived from DLE, IMREG-1, has been shown to enhance cell mediated immunity (22). In vitro studies have shown that both cells murine recipients and humans treated for herpes zoster virus infection secrete gamma-interferon in response to transfer factors (23). Studies have also suggested that production of transfer factors, but not the immunologic activities, is regulated by immune response (Ir) genes. (24).

Wagner G, et al. Transfer factor for adjuvant immunotherapy in cervical cancer. Cancer Detect Prev Suppl 1987; 1: 373-6.
In a prospective randomized double-blind study of 60 patients with invasive cervical cancer, one group was treated with transfer factor derived from leukocytes of the patients' husbands, while the control group was treated with placebo. Survival rates among members of the treatment group were significantly higher than those of the control group within the first two years after radical hysterectomy. When the collectives were subdivided, significant differences were found in patients under age 35 and in patients with Stage I disease.

Whyte RI, et al. Adjuvant treatment using transfer factor for bronchogenic carcinoma: long-term follow-up. Ann Thorac Surg 1992; 53(3): 391-6.
Between 1976 and 1982, 63 patients who underwent pulmonary resection, mediastinal lymph node dissection and, in some cases, mediastinal irradiation, were randomized into two groups. The treatment group received transfer factor at three-month intervals after operation, while the control group received saline solution at identical intervals. The two-year, five-year and 10-year survival rates in patients receiving transfer factor were not statistically significant when compared with the survival rates of the control group, though the differences between the groups were large enough to merit further research.

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Bottom Line: Transfer factors have not been shown to treat or prevent cancer.

Transfer factors are a group of proteins produced by cells of immune system. Some studies have shown that transfer factors can be used for treatment of herpes, infections in children, chronic fatigue syndrome, and yeast infections. They may also boost the immune system in patients with AIDS. More research is needed to determine the anticancer effects of transfer factors.

Cancer treatment
A well designed trial of 168 patients with Stage I or Stage II melanoma found transfer factor ineffective when used after surgery. Within 90 days of surgery, patients began treatment with either transfer factor or placebo. Treatment continued until patients had been disease-free for two years or until metastasis (spread of tumor cells to other parts of the body). Patients in the placebo group had the highest survival rates compared to those on transfer factor.

Another study was done to find out the effect of immunotherapy with transfer factor in addition to radiotherapy in 100 patients with Stage III nasopharyngeal carcinoma (NPC). Patients were randomized to receive either radiotherapy alone or radiotherapy along with an 18-month course of transfer factor. Patients were followed for at least five years, but no significant difference in disease-free survival or survival was observed between the two groups.